Weirs are overflow structures, which alter the discharge so that flow rate can be calculated, flood can be prevented, or even make a body of water more navigable. Measurements of discharge are known based on the surface profile of the water. For estimation of discharge over the weir, weir coefficient is required. In this report only the broad crested weir is focused on. Design and the analysis of this weir are shown in the report. It was found that the broad-crested weir is best for measuring discharge in small medium channels. Flow over a broad-crested weir is highly dependent on the weirís geometry, itís a useful hydraulic tool which enables engineers to control water height, velocity, and most importantly they can be used to calculate discharge. Hydraulic structures such as weirs, flumes, and pipes, may cause the flow upstream of the structure to rise above the normal flow depth this is a common property.